Child presents with abrupt high fever (38.9°C to 40°C [102°F to 104°F]) with a seizure at home. Now toddler is alert and oriented. He is fussy and complains of a sore throat and dysphagia. On exam of the throat, you find ulcerative lesions (vesicles rupture, leaving painful ulcers on the posterior pharynx, soft palate, uvula. Anterior mouth is spared. What is the diagnosis and treatment?

a) Herpangina; Supportive care
b) Hand, foot, and mouth disease; Supportive care
c) Scarlet fever; Penicillin or amoxicillin
d) Varicella; Antiviral therapy